Note: Descriptions are shown in the official language in which they were submitted.
CA 02238649 1998-OS-26
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MOTORIZED SPINDLE WITH INDEXING FIXTURE
Field of the Invention
' This invention relates to motorized spindles for
driving workpieces, such as crankshafts, and for indexing such
' workpieces relative to a grinding tool, so that each crank pin
on the crank shaft is accurately ground, in sequence.
Background of the Invention
In known grinding machines, such as shown in FT_G. 1 of
U.S. Patent 5,405,282, granted April 11, 1995 to William W.
Pflager, and assigned to the assignee of the instant application,
an abrasive grinding wheel (28) is rotatably mounted upon a wheel
head (26) for translation relative to a cam shaft (22), that is
I5 ground to a desired size and shape. The workpiece is retained
between a headstock (18) and a footstock, and the wheel head,
with the grinding wheel, is translated by a nut (40) and lead
screw (42) arrangement. The unit is secured to the wheel head,
and the lead screw is driven by a motor (44), coupled to the end
of the lead screw remote from the nut. The motor, which may be
numerically controlled, rotates the lead screw relative to the
nut, in either clockwise or counterclockwise fashion, and thus
linearly translates the abrasive grinding wheel relative to the
workpiece. The grinding wheel may be advanced along its axle
(30) to grind each lobe in the camshaft, in sequence.
Other grinding machines employ an endless abrasive belt
to grind each lobe, or eccentric surface, on a camshaft, in
sequence. Recently, grinding machines relying upon. several,
simultaneously operated, parallel, abrasive grinding belts have
been employed, with. attendant savings in operating costs and
higher output per machine. Representative multiple belt grinders
are disclosed in U.S. Patent 5,142,827, granted September 1992
to Phillips and in U.S. Patent 5,359,813, granted November 1,
1994 to R.E. Kaiser, Jr. and Steven G. Lueckeman.
The foregoing grinding machines function satisfactorily
for cam shafts, which have a central axis of rotation extending
longitudinally through the journals at the opposite ends of the
shaft to be ground. One journal is retained in a chuck opera-
tively associated with the head stock, while the other journal
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2
is retained in a chuck operatively associated with the tail
stock. Drive motors in the head stock and tail stock rotate the
cam shaft, relative to the grinding tool, and programs stored in
computers that control the drive motors provide the information
necessa=-y to grind the cam shafts to the desired configuration.
The cam shafts are angularly aligned relative to the
chucks, to establish a fixed reference point for the subsecruent
grinding operations. The reference point is usually established
by cooperation between interengaging mechanical members formed
in the journal bearings of the cam shaft and the chucks. The
mechanical members might assume the form of a key milled in the
journal bearing, and a key way in the chuck, or vice versa. Pins
and slots, balls that are spring-loaded into engagement with
dimples or locating holes in the j ournal bearings , etc . have also
been utilized.
Whereas cam shaft grinding machines have become better
suited to high speed processing, on automated or semi-automated
machines, with reductions in the number of skilled technical
personnel to operate and oversee same, similar advances have not
been realized with crank shaft grinding machines.
Crank shafts, which are farmed by iron castings or by
forged steel techniques, are considerably heavier and more
cumbersome to manipulate than cam shafts. Eccentrics are formed
on the crank shaft, inboard of the main bearings, to provide
bearing surfaces for the connecting rods of an automotive
vehicle. Crank shafts also introduce difficult geometric
relationships, for while a first longitudinal axis is drawn
between the journals at the opposite ends of the crank shaft,
other longitudinal axes are drawn through the center lines of the
pins spaced along the crank shaft. The pins to be ground are
radially and longitudinally disposed about the first, or central,
longitudinal axis, and the longitudinal axes of the pins must be
maintained parallel to the first, or central, longitudinal axis.
The crank shaft rotates about the pin axis, while the first, or =
central, Longitudinal axis rotates eccentrically about the pin.
The grinding tool, which abrades a limited amount of metal from
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3
each pin, only establishes contact with the pin to be ground
after the pin has beer_ indexed into the appropriate position.
Known crank shaft grinding machines, employ mechanical
keys and cooperating holes, and/or similar interengaging
mechanical components, to properly align the crank shafts within
the chucks in the head stock and foot stock of, the grinding
machines, and thereby establish a zero reference angle for
subsequent grinding operations.
Complicated fixtures were employed to properly position
the pin to be ground relative to the grinding tool. The accurate
grinding of the crank shaft, within acceptable tolerances was
slow, time-consuming, and required highly trained, technically
skilled operators.
The difficul ti es inherent in grinding crank shafts have
been compounded recentl y, when the customers for the ground crank
shafts, typically automobile, truck, farm vehicle manufacturers,
construction ec_ruipment manufacturers, etc., have insisted that
the mechanical keys, holes, etc. which are previously used to
establish a zero reference angle be eliminated_ Consequently,
a new and different technique had to be utilized to hold the
crank shaft and establish the zero reference angle.
- pC'T/~ 9 6 / ~ ~ 2 7 5
I~AA~ 13 r td 1998
4
SUI~iARY OF THE INVENTION AND ADVANTAGES
The instant invention pertains to a motorized spindle,
comprising a spindle body and an indexing fixture. The same
motor drives the spindle body and indexing fixture, as a unit,
or drives the indexing fixture relative to the spindle body. The
motor delivers power directly to a primary drive shaft aligned
with the center line of the spindle body, and indirectly to a
secondary drive shaft aligned with the center line of the main
bearings, or journals, on the opposite ends of a crank shaft.
l0 An off-set coupling efficiently transfers power from
the primary drive shaft to the secondary drive shaft, while
maintaining the parallel relationship therebetween. The coupling
includes parallel links installed 90° out of phase with each
other. In a preferred form, such coupling is a Schmidt off-set
coupling. Cooperating keys and key ways in the interior of the
motorized spindle retain the components in alignment.
Furthermore, since the ultimate end-user of the crank
shaft requires the journals, and crank pins, to be cylindrical
in shape, the journals, and crank pins, of the crank shafts must
be maintained in unblemished, cylindrical shape at all times.
The key ways, or holes, previously formed on the end of the crank
shaft, to facilitate establishment of a zero angle reference
point for all grinding operations, are no longer acceptable to
the customers for the ground crank shafts.
Consequently, a reference pad is now milled, or
otherwise formed, on the crank pin web situated between the
journal and the first pin on the crank shaft. A work rest forces
such reference pad against a stop to define a zero angle
reference point, in conjunction with the upwardly opening bearing
block that receives a journal on the crank shaft.
The indexing fixture, which is intermittently advanced,
rotates the pin to be ground to a position coincident with the
center line of the spindle body. During grinding operations, the
spindle body and indexing fixture are retained together by a
locking mechanism, and rotate as a unitary mechanism. During
indexing operations, the indexing fixture is disengaged from, and
AMENDED ~HEE7.
9611~2~' ~
~3rt~19yb
adjusted relative to, the spindle body, when the locking
mechanism is released.
The degree of angularity for such rotation, from 0° to
360°, is determined by a within the locking mechanism,
comprising, inter alia, opposing jaws with cooperating,
interengaging teeth spaced at 3° intervals. The opposing jaws
are normally urged into meshing, or locking, engagement by the
application of pressurized fluid. However, the fluid pressure
is relieved, and/or reversed, when necessary, to allow
disengagement of, and then relative rotation, between the
opposing jaws. The extent of angular adjustment moves the pin
to be ground to the desired angular relationship relative to the
grinding tool. After such adjustment, the opposing jaws are
-~~ forced together and the angular relationship of the pin to the
grinding tool is maintained during the grinding operation.
The jaws of the circle divider are forced together, to
retain the indexing mechanism immobile, by the greatest force
employed within the instant machine. Each succeeding locking,
or retaining, mechanism found in the motorized spindle operates
at a lower force. This step-wise reduction in forces produces
a force path to ground effect within the motorized spindle, which
tends to keep all components of the indexing fixture and
motorized spindle united as a unitary device.
The drive motor for the motorized spindle and indexing
fixture is bolted, or otherwise secured, to the rear end of the
primary shaft. The primary shaft rotates within a squeeze
bushing that surrounds the primary shaft. Pressure is imparted
to the squeeze bushing to lock the primary shaft, after the
circle-divider is clamped into angular position. The primary
shaft, in turn, through the squeeze bushing, drives the spindle
body.
When the primary shaft and secondary shaft are driven
in unison, through the coupling, the circle divider controls the
angular positioning of each crank pin relative to the grinding
tool. A threaded bolt and complementary nut provide throw
adjustment for the pin relative to the first, or main, bearing
axis.
AMENDED SHEET
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6
The foregoing motorized spindle may function as a head
stock, and a similar motorized spindle may function as a tail
stock. The head stock and tail stock are be coupled together, ,
in a master-slave relationship, so that the crank shaft can be
accurately ground, in a slip-free manner, within tolerances ,
previously unobtainable under high-speed production conditions.
Yet other advantages of the instant motorized spindle
will become readily apparent to the skilled artisan when the
appended drawings are construed in harmony with the ensuing
30 description of a preferred embodiment.
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BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is an end elevational view of the main bearing
shaft of the crar_k shaft to be-ground, such view further showing
the mechani sm for aligning the main bearing shaft relative to the
primary drive shaft of the motorized spindle constructed in
accordance with the principles of the present invention;
FIG. 2 is an end elevational view of the indexing
fixture of the motorized spindle, such view taken along line II-
II in FIG. 5A, and showing the clamping mechanism for retaining
the main bearing shaft within the cradle;
FIG. 3 is an end elevational view of the indexing
fixture with the main bearing shaft in the cradle and the pin to
be ground positioned therebelow so that the grinding tool can
contact and grind same;
FIG. 4 is a schematic view showing the relationship
between the main bearing axis upon which the crank shaft is
supported, and the axes of the pins which are coincident with the
center line of the primary drive shaft when the pins are in
position to be ground;
FIG. 5A is a side elevational view, with fragmentary
portions removed, of the indexing fixture with the secondary
drive shaft secured thereto;
FIG. 5B and FIG. 5C are complementary cross-sectional
views of the indexing fixture and the spindle body showing the
primary drive shaft, the secondary drive shaft, and the coupling
therebetween;
FIG. 6 is an exploded perspective view of the coupling
that joins the primary drive shaft to the secondary drive shaft;
PiCllllS 9 6 l 1 R 2 7 ~
~6 13 ~ ~ ~ 19~
FIG. 7A and 78 show the stroke adjustment mechanism for
shifting the indexing fixture relative to the spindle body;
FIG. 8A shows the within the locking mechanism for the
indexing fixture being pressured to force the jaws of such
mechanism together, while FIG. 88 shows the two halves being
forced apart;
FIG. 8C shows the jaws of the within the locking
mechanism in engaged position, while FIG. 8D shows the two jaws
in disengaged position; and
FIG. 9 is a schematic representation of the control
circuitry for coordinating the operation of the pair of motorized
spindles that align, index, and rotate the crank shaft while
grinding operations are performed thereon.
_-
AMENDED SHEET
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9
DESCRIPTION OZ'' THE PREFERRED EM80DIMENT
FIGS. 1 and 5A show a fragment of a conventional crank
shaft, indicated general:Ly by reference numeral 10, .that is ,to
be ground by a known abrading tool, such as a grinding wheel.
The crank shaft is retained in proper position relative to the '
grinding wheel by a first motorized spindle, commonly called a.
head stock, anc a second motorized spindly; commonly called a
tail stock. The grinding wheel may be indexed relative to crank
shaft 10, or vice versa, parallel to the spindle axes, so that
the several pins on the crank shaft are ground in serial fashion.
Only the first motorized spindle is shown in~FIGS.~l-8 for the
sake of clarity, but FICJ. 9 shows the interrelationship between
a pair of motorized spindles.
Cran:lc shaft 10 includes a main bearing shat 12, crank
pin webs 14 located inboard of main bearings 12, and a 5er~es of
crank pins 16. A referen.c:e pad 18 is milled into crank pin web
14 below shaft 12 and ad;~acent to pin 16, as shown in FIG. 1.
With the motorized spindles stopped, and the clamps in
opened, or non-engaged positions, the main bearing shaft 12 or
cranlc shaft 10 is inserted, via gravity, into bearing blocJc 20,
shown in FIGS: 2 arid 3. Bearing block 20 has a semi-circular
cut-out 21 that accepts bearing shaft 12, and wear resistant
bearings 23 are spaced about cut-out 21, so that crankshaft 12
can be located accurately,! therein.
After shaft 12 is seated with pin 16 resting therebe-
low, as shown in FIG. 1, worJc rest 22 is operated toward part 24
so that the work rest pivots about pin 2~6 and pad 28 presses
against pin 16. Crank pi,n web 14 is thus rotated so that
reference.pad ZS contact: stop 30, and the axes of rotation for
shaft 12 and pins) 16, are established along a common center
line, as showr~ in FIG: 1. The extent of movement of pin l6 is
ascertained by comparing the solid outline of crank pin web 14
with the dotted outline of crank pin web l4 in FIG. 1.
FTG. 2 shows an indexing fixture, indicated generally
by reference numeral .29. Indexing fixture 29 includes a first
clamping arm 32 that is pivoted about its axis-34 so that clamp
shoe ' 36 presses, agains shaft 12 . Second clamping arm 38 is
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ZO
pivoted about its axis 40 so that clamp shoe 42 presses against
shaft 12. Clamp arms 32, 38 operate simultaneously. Bearing
block 20, bearings 23, and clamp shoes 36, 42 retain shaft I2
securely seated within cut-out 21 to maintain shaft location
within the indexing fixture.
Hydraulic cylinder 44, when pressurized, extends piston
46 which is secured by pin 48.to the lower end of first arm 32.
Similarly, hydraulic cylinder 50, when pressurized, extends
piston 52 which is secured by pin 54 to the lower end of second
arm 38. Clamping arms 32, 38 are shown, in dotted outline, in.
the "opened" position, which allows free ingress of the crank
shaf t 10 , including main bearing shaf t 12 , into bearing block 2 0 .
After main bearing shaft 12 is seated, then the clamping arms are
pressurized, through cylinders 44 and 50, to "closed" position,
25 wherein clamp shoes 36, 42 press downwardly upon shaft 12.
Blade 56 projects upwardly from the free end of
clamping arm 32, and switches 58, 60 respond to the movement of
blade 56 to detect whether the clamping arms are opened, or
closed. In a similar fashion, blade 62 projects upwardly from
the free end of clamping arm 38, and switches 64, 66 respond to
the movement of blade 62.
The size relationship and the uniczue spatial relation-
ship, between indexing fixture 29, and the main spindle body,
indicated generally by reference numeral 68, is also shown in
FTG. 2. Indexing fixture 29 is mounted upon the forward end of
main spindle body 68, and is operatively associated therewith.
Indexing fixture 29, and main spindle body 68, and their
constituent parts, form a motorized spindle.
FIG. 3 depicts the spatial relationships achieved by
the instant motorized spindle that are essential to its success
ful operation.. The common center lne extending through main
bearing shaft 12 and pin 16, depending therebelow, establishes
a zero angle reference point for all subsequent grinding
operations effectuated on crank shaft 10. Main bearing shaft 12
is seated in cut-out 21 in bearing block 20, and clamping arms
32, 38 retain the shaft securely seated in the bearing block.
The depending pin 16 is coincident with the primary drive shaft
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11
(not shown) in main spindle body 68, while main bearing shaft l2
is coincident with the secondary drive shaft (not shown) in
indexing fixture 29. Indexing fixture 29 is indexed by the
secondary drive shaft, about main bearing shaft 12, and main
spindle body 68, to place the pin 16 to be ground in a position
i
below main bearing shaft 12 and tangential to rotary grinding
wheel 70. The pins on crank shaft 3.0 are ground, seriatim, by
grinding wheel 70 as each pin is indexed to the position shown
in FIG. 3, and Longitudinally advanced, relative to grinding
wheel 70, shown in phantom outline.
FIG. 4 indicates that pins 16 are angularly distributed
about the main bearing shaft 12 of crank shaft 10 at a common
radial distance. Indexing fixture 29 is indexed to position the
pin 16 to be ground at a position coincident with the primary
drive shaft (not shown) and/or center line of main spindle body
68. Indexing fixture 29 and main spindle.bcdy 68 usually rotate
in a unitary fashion, when power is suppl i ed to the motorized
spindle. However, when indexing fixture 29 is indexed to advance
the pin I6 to be ground at the reauisite position, indexing
fixture 29 is disengaged from main spindle body 68 and is driven
relative thereto. The mechanisms for implementing this novel
method of operation are shown in FIGS. 5-9, discussed hereinaf-
ter.
FIG. 5A shows the indexing fixture 29 in side eleva-
Lion, with a fragment broken away to show the connection between
indexing fixture 29 and main spindle body 68. Steps 72, 74 and
76 are defined in the rear face of indexing fixture 29, and a
central chamber 78 is defined in the interior of the fixture.
An axial bore 80 extends from the stepped rear surface of the
fixture into the central chamber 78.
Forwardly extending nose 82 on index spindle body 116
fits into axial bore 80, and secondary drive shaft 84 extends
through the nose and is secured to indexing fixture 29. Bolts
92, 93 extend through secondary drive shaft flange 88 and into
indexing fixture 29 in the vicinity of chamber 78. Secondary
shaft 84 is thus secured to indexing fixture 29 to deliver
driving forces thereto. Seals~94, 96 are interposed between nose
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12
82 and bore 80; the seals are used to connect a hydraulic circuit
(not shown) from the main spindle hose to indexing fixture 29.
FIGS. 5B and 5C are drawn on a smaller scale than FIG.
5A, and show main spindle body 68 with indexing fixture 29
removed therefrom, for the sake of clarity. Counterweights are ,
also removed from view in FIGS. 5B and 5C so that attention can
be focused upon main spindle body 68.
Viewing FIGS . 5i3 and 5C together, and starting from the
rear of main spindle body 68, the body includes a servomotor 98,
such as a brushless thirty-two pole motor, that rotates primary
drive shaft 100. The primary drive shaft 100 is located on the
center line of main spindle body 68, and is aligned longitudinal-
ly with the axes of crank pins 16 on crank shaft 10. An encoder
I02 is operative) y associated with servomotor 98 to r2gul ate the
rotational speed, and/or identify the angular position, of shaft
100.
A hydraulic pick-up.104 encircles the rear segment of
main spindle 110. A scrueeze bushing 108, which assumes the form
of a cylinder with longitudinally extending, deformable fingers,
slips over primary shaft 100 so that primary shaft 100 rotates
within busing I08. Shaft 100 extends 'through bearings 106 in
main spindle 110, and the associated components, in a rigid, sag
free manner. A channel 112 extends radially through hydraulic
pick-up 104, and main spindle 110 to communicate with chamber
114, which surrounds sc_rueeze bushing. 108. When fluid pressure
is introduced into channel 112 and flows into chamber 114,
bushing 108 engages primary shaft 100 and retains same in fixed,
immobile position. The other components of the index mechanism
that are connected to main spindle 110, either directly or
indirectly, are also retained motionless.
Main spindle 110 t~=-rminates in enlarged flange 111,
which abuts against index spindle 1I6, over an extended surface. _
Index spindle I16 and flange 111 may be keyed, or otherwise
joined together, so that the spindle rotates as a unit. A
stepped, outwardly opening, cavity 118 is defined at the forward
end of flange 111 of main spindle 110, and a stepped cavity 120
is formed in the abutting portion of index spindle 116.
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Secondary drive shaft 84 extends through bore 80 in index spindle
116, and flange 88 is bolted to indexing fixture 29; only the
outline of a portion of indexing fixture 29 is shown in FIG. 5B.
Secondary drive shaft 84 is parallel to, but spaced from, primary
drive shaft 100, and an off-set coupling, indicated generally
by
reference numeral 122, fits into cavities 118, 120 in spindles
1.10, 116, and effectively transfers power from shaft 3.00 to
shaft
84 in an efficient, slip-free manner.
Off-set coupling 122 may assume different forms, but
a preferred coupling, that has functioned effectively under test
conditions, is manufactured, and distributed by, ZERO-MAx Company
of Minneapolis, Minnesota. As shown in greater detail in FIG.
6, coupling 122 includes an inlet adapter 124 that is secured
to
primary drive shaft 100, ar_d an outlet adapter 126 that is
secured to secondary drive shaft 84. Discs 130, 132 and 134 have
central apertures, and are located parallel to each other, and
perpendicular to primary drive shaft 100 and secondary drive
shaft 84. Several pairs of parallel links 136, 138; 140, 142;
144, 146; are spaced about discs 130, 132, 134, and pins 148,
150, 152, 154, I56, etc., pass through the links and secure the
links between adjacent discs. In a preferred embodiment, four
pairs of parallel links are used, spaced 90 apart, to provide
for precise transmission of torque and velocity between the
shafts .
FIG. 7A shows further details of main spindle body 68,
particularly in the vicinity of cavities 118, 120 defined in the
abutting surfaces of flange 111 of main spindle 110 and index
spindle 116. Pins 16 on crank shaft 10 may be adjusted
radially, at different distances from main bearing shaft 12, for
different crankshafts. In order to adjust the position of the
crank shaft 10 relative to the center line of main spindle 110,
a threaded bolt 158 is advanced, or retracted, relative to
threaded aperture 160, which extends into index spindle 116. A
carrier 162 supports bolt 158.
Index spindle 116 is moved relative to main spindle
110, and~a clearance 166 is visible in FIG. 7B. The stepped
cavities i18, 120 overlap somewhat, so that coupling 122 is
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14
unaffected by the relative movement. Key I68 on carrier 162
rides clang key, way 170 to facilitate accurate alignment, and key
171 rides along key way 173.
FIGS . 7A and 7B illustrate the circle divider mechanism
I74 located at the interface of index spindle 1I6 and indexing
r
fixture 29. Mechanism 174 includes a first annular support 176,
with a stepped profile, which abuts steps 72, 74, 76 of indexing
fixture 29, and is secured thereto. A second annular support
I78, with a complementary configuration, is retained withi n index
i0 spindle 116.
FIGS . 8A and 8B illustrate the circle divider mechanism
174 on a larger scale. Channels 180, 182 are drilled through
support 176; channel 180 communicates with chamber I84, while
channel 182 communicates with passage 386. Ball bearings 188
I5 allow supports 1.76, 178 to rotate easily.
FIGS. 8C and 8D show the two jaws 190, 192 of a circle
divider mechanism. Each jaw 190, 192 has triangular, or saw
tooth teeth, that engage with complementary~surfaces on the
mating jaw. The circle divider mechanism is also known as a
20 Hirth coupling.
The operation of circle divider mechanism 274 can be
gleaned from FIGS. 8A-8D. In FIG. 8A, pressure is normally
supplied through channel I80 to chamber 184, so that jaws 190 are
forced together, and indexing fixture 29 and index spindle 116
25 rotate together in response to the torque, delivered by shafts
100, 84 through coupling 122. The fixture and index spindle are
normally retained in locking engagement, and rotate as a unitary
motorized spindle. Circle-divider mechanisms can be purchased
from A.G. Davis Gage and Engineering Co. of Hazel Park, Michigan.
30 Intermittently, after the grinding of a pin I6 on tine
crank shaft 10 has been completed, the need arises to index
another_ pin to be ground to the position hown in FIG. 3. Throw
adjust housing 69 and main spindle 110 are then held stationery,
by an external latch mechanism (not shown). Pressure is no
35 longer supplied to channel 180 in support I76, as is usual, and '
as indicated by the directional arrows in FIG. 8A. In lieu
thereof, pressure is supplied to channel 182, and passage 186,
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to disengage jaws 390, 192, as shown by the directional arrows
in FIG. 8B, and as suggested by the spacing between the disen-
paged jaws 190, 7.92 in FIG. 8D.
While the jaws are disengaged, and indexing fixture 29
5 is freed from index spindle 116, torque is supplied to indexing
.fixture 29 via primary drive shaft 100, coupling 122, and
secondary drive shaft 84. Flange 88 thus delivers a rotational
force to indexing fixture 29 of sufficient magnitude to index a
fresh crank pin 16 to be ground into a position below main
10 bearing shaft 12 and coincident with main spindle 110.
After indexing fixture 29 has been rotated, pressure
is shut off in channel 182, also. Pressure is re-introduced into
channel 180, and chamber 184, to force jaws 190, 192 together.
Next pressure is returned to chamber 114, through passage 112,
15 clamping squeeze bushing 108 to primary drive shaft 100. The
engagement of jaws 190, 192 couples indexing fixture 29 to index
spindle 116, and the external latch mechanism previously coupled
to throw adjust housing 69 and main spindle 110, is released and
the coupled assemblies rotate as a unitary motorized spindle.
Servomotor 98 drives the motorized spindle, when the assemblies
are coupled and rotate in unitary fashion, and also furnishes the
torque to rotate the indexing fixture, in an intermittent
fashion.
FIG. 9 suggests that the motorized spindle constructed
in accordance with the principles of the invention can function
as a head stock I94, or can function as a tail stock 196. The
head stock 194 and tail stock 196 can be coupled together, via
grind/index switch 198, slave made switch 200, and the related
circuitry for controlling the head stock and tail stock.
Other modifications, revisions, and refinements will
occur to the skilled artisan. Consequently, the appended claims
should be construed in a manner consistent with the significant
advantages in crank shaft grinding, realized by the instant
invention. Thus, the claims should be construed liberally, and
should not be restricted to their literal, exact terminology.
